Ultrasmall Surface-Charge-Modified Tantalum Oxide Nanoparticles for the Assessment of Articular Cartilage Using Contrast-Enhanced Computed Tomography

J Jäntti; J Tuppurainen; A Joenathan; HPP Leskinen; AM Cagnoni; H Mertano; M Poimala; E Nippolainen; IO Afara; JTJ Honkanen; H Matikka; J Töyräs; BD Snyder; KS Stok; BB Nelson; MW Grinstaff; JTA Mäkelä

Journal article

Ultrasmall Surface-Charge-Modified Tantalum Oxide Nanoparticles for the Assessment of Articular Cartilage Using Contrast-Enhanced Computed Tomography

J Jäntti, J Tuppurainen, A Joenathan, HPP Leskinen, AM Cagnoni, H Mertano, M Poimala, E Nippolainen, IO Afara, JTJ Honkanen, H Matikka, J Töyräs, BD Snyder, KS Stok, BB Nelson, MW Grinstaff, JTA Mäkelä

ACS Nano | Published : 2026

DOI: 10.1021/acsnano.5c15722

Abstract

The size and surface properties of nanoparticles (NPs) define their interactions with biological tissues and impact their effectiveness for targeted imaging and therapeutic applications. Here, we investigate ultrasmall tantalum oxide nanoparticles (Ta2O5-NPs) as computed tomography (CT) contrast agents and the effects of NP surface charge on diffusion in ex vivo human cartilage samples, as well as after intra-articular administration in intact rabbit and equine joints. Controlled hydrolysis of tantalum(V) ethoxide, followed by coating with positively charged trimethylammonium and nonionic poly(ethylene glycol) (PEG) ligands at different ratios, affords the approximately 3 nm positively charg..

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